The story is fairly simple, as this is mostly a slice-of-life romance. The little story that is here is driven by the two fascinating characters. Young woman takes over her father's old bookshop, meets a bookish boy who is oddly mature for his age, and immediately proposes to him. He's taken back, but intrigued enough to start seeing her. It turns out that they both have similarly bad family backgrounds, both love books, and they use that to slowly build their relationship.
It's simple, but very well written. My only regret is that the manga wasn't longer. The story ended at a reasonable point, and most of her background was fully explored, but his was left somewhat vague. Besides, I loved the characters enough, I would have thoroughly enjoyed spending more time with them.
The art is solid, but unspectacular. The pacing was good, it ended well (if a little abruptly). There is almost no fan-service here (they even make a joke about that at one point), and the relationship remains remarkably chaste.
In other words, if you like a good vanilla romance, and the age-gap isn't a massive turn-off for you, then there is no reason not to give this a try.
